Scenarios for meeting ambitious climate targets rely on large-scale deployment of negative emissions technologies (NETs), including direct air capture (DAC). However, the tradeoffs between food, water and energy created by deploying different NETs are unclear. Here we show that DAC could provide up to 3 GtCO₂ yr⁻¹ of negative emissions by 2035—equivalent to 7% of 2019 global CO₂ emissions—based on current-day assumptions regarding price and performance. DAC in particular could exacerbate demand for energy and water, yet it would avoid the most severe market-mediated effects of land-use competition from bioenergy with carbon capture and storage and afforestation. This could result in staple food crop prices rising by approximately fivefold relative to 2010 levels in many parts of the Global South, raising equity concerns about the deployment of NETs. These results highlight that delays in aggressive global mitigation action greatly increase the requirement for DAC to meet climate targets, and correspondingly, energy and water impacts.

实现雄心勃勃的气候目标的方案取决于大规模部署负排放技术（NET），包括直接空气捕获（DAC）。但是，尚不清楚通过部署不同的NET来在食品，水和能源之间进行权衡。在这里，我们表明，到2035年，DAC最多可提供3 GtCO ₂ yr ^-1的负排放量，相当于2019年全球CO _2的7％。排放量-基于有关价格和性能的当前假设。特别是发援会可以加剧对能源和水的需求，但它将避免生物利用碳捕集，封存和造林带来的最严重的市场介导的土地利用竞争。这可能导致全球南方许多地区的主要粮食作物价格比2010年的水平上涨约五倍，这引起了人们对NETs部署的担忧。这些结果表明，积极的全球缓解行动的延迟大大增加了发援会达到气候目标的要求，并相应地增加了能源和水的影响。